required no real effort: In 2012, Italian researchers found that breathing at six breaths a minute had powerful effects at high altitudes of 17,000 feet. The technique not only significantly reduced blood pressure but also boosted oxygen saturation in the blood. Grzegorz Bilo et al., “Effects of Slow Deep Breathing at High Altitude on Oxygen Saturation, Pulmonary and Systemic Hemodynamics,” PLoS One 7, no. 11 (Nov. 2012): e49074.
